The effect of loss of the glucose-monitoring neurons in the anterior cingulate cortex: Physiologic challenges induce complex feeding-metabolic alterations after local streptozotocin microinjection in rats

Abstract

The anterior cingulate cortex (ACC) is interrelated to limbic structures, parts of the central glucose-monitoring (GM) network. GM neurons, postulated to exist here, are hypothesised to participate in regulatory functions, such as the central control of feeding and metabolism. In the present experiments, GM neurons were identified and examined in the ACC by means of the multibarreled microelectrophoretic technique. After bilateral ACC microinjection of streptozotocin (STZ), glucose tolerance tests (GTTs), and determination of relevant plasma metabolite concentrations were performed. Body weights were measured at regular time points during the GTT experiment. Ten percent of the neurons - 30 of 282 recorded cells - responded to the administration of D-glucose, thus, declared to be the GM units. The peak values and dynamics of the GTT blood glucose curves, the plasma metabolite concentrations, and the weight gain were pathologically altered in the STZ treated animals. Our recording experiments revealed the existence of GM neurons in the anterior cingulate cortex. STZ induced selective destruction of these chemosensory cells resulted in feeding and metabolic alterations. The present findings indicate distinguished significance of the cingulate cortical GM neurons in adaptive processes of maintenance of the homeostatic balance.

Keywords: Anterior cingulate cortex; Glucose tolerance test; Glucose-monitoring neuron; Homeostasis; Plasma metabolites; Streptozotocin.